I know it's taken a while, but I'm back from vacation and back from youth camp so I can pick up with posting some of our VBS Mad Science topics. Actually, I was reminded while I was at camp that I needed to do this.
My small vortex generator is a 16 oz. Styrofoam cup with a nickel-sized hole cut in one end and a membrane made from a sandwich bag rubber-banded to the other end.
While at camp, I was in the adult seminar and a gentleman walked in with one of these:
It's a good thing my daughters weren't there because at the end of the session, I chased the man down and asked if I could check it out!!
Back to VBS: We studied air on the day that we covered the parable of the Good Samaritan. Our lessons called it "The Roadside Rescue" and the 'Word on the Street' that day was COMPASSION. The wounded man felt invisible to the first couple of people who passed him by. Now they may have actually THOUGHT about helping him, but they didn't actually DO anything. We picked AIR as the science topic of the day because it's invisible itself, but it is visible by what it can do.
Above you see the picture of our small vortex generator. When you tap on the plastic membrane, it quickly compresses the air in the cup and it's forced out the hole in the other end. Just a gentle tap can move your hair around and even blow out a candle. (Try it on your next birthday cake!!) We made a larger vortex generator out of a 5 gallon bucket and a piece of shower curtain held in place with a bungee cord. The hole in the bottom of the bucket was about 3 inches in diameter. The larger one is good for knocking cups off the heads or out of the hands of your volunteers.
If you are truly ambitious, you can try it with a much larger garbage can. It needs to be round and you might have to add a shoulder strap for handling it.
Air and curved surfaces are a great combination. You can make a ping pong ball hover over your hair drier or a beach ball over a box fan. Balloons are a bit unstable, but if you drop a penny inside the balloon before you blow it up then place it over the fan, it will SOAR.
Air, even though it's invisible, is capable of doing lots of stuff that we can see. Our compassion needs to be visible by what we DO with it, just like in "The Roadside Rescue."